The invention relates to a directional control valve assembly having a plurality of control valves.
A generic stack valve assembly is shown in U.S. Pat. No. 3,111,139. Several directional control valves are each constructed as a complete encapsulated unit and are clamped onto a common base element by screws. The base element, in turn, is also composed of several pieces each having a planar face in fluidic contact with a directional control valve and is provided with pressure and load connection paths. A base part of each directional control valve has a corresponding planar face having holes or valve paths which match the connection paths of the base element face. Sealing of the face joint from the outside and between the various connection paths is ensured by a separate flat seal for each directional control valve. The seal is elaborate because of the numerous perforations, in conjunction with the clamping force of the screws.
A form-fitting fluidic contacting of directional control valves having a common one-piece base element is disclosed in German Published Unexamined Patent Application No. 3,218,006. In this document, connection stubs of the directional control valves are inserted into corresponding sockets of the base element constructed as under pressure distributor. The sealing from the outside is effected at the same time by an annular seal between connection stub and socket.
Even in the latter arrangement, however, the directional control valves are plugged into the common under pressure distributor as encapsulated units which are in each case complete. The simple seal can be used functionally reliably in this case in combination with the fluidic plug-in connection only because a pneumatic under pressure is applied to the distributor.
An object of the present invention is to provide a generic directional control valve assembly wherein in addition to the base element, other assembly parts can be jointly used for several directional control valves or can be produced as standard parts and, in addition, reliable sealing of the assembly is achieved by simple sealing means needed for few sealing joints.
These and other objects are obtained by a valve assembly having a plurality of electromagnetically actuated directional control valves clamped between a common base element and a cover plate. The valve includes a valve body and a valve actuator having an armature surrounding the valve body and a magnetic tube surrounding the armature. A valve seat is in a recess or socket in the base element between pressure connection and load connection paths. The valve body and magnetic tubes are fluidically sealed in the recesses and position the valve body with respect to the valve seat. A plurality of magnetic jackets are separate from the valve actuators and are joined to each other in groups to form a coherent magnetic jacket component. The distance between the individual jackets corresponds to the distance between the sockets and are clamped between the base element and the cover plate.
Due to the stack design of the assembly, the magnetic jackets, which are combined into one component, and the cover plate used for clamping in the valve actuators are also jointly used for all valves in addition to the fluidic base element. This provides the possibility of using stampings or moldings for the magnetic circuits of the valves. Thus, for example, the magnetic tubes can be produced as extruded parts which do not require any subsequent surface machining for carrying the armature. The magnetic jackets are produced coherently, for example from pressed sheet-metal parts.
The base element is thus a component of the directional control valves themselves. For the base element, cutting machining is required as a rule at least at the sockets for the magnetic tubes (pegs or recesses). But the effort for sealing the directional control valves and their path connections is reduced due to the sandwich construction, for example in the advantageous direct connection of the assembly to a fluidic conductor plate, for example for controlling an automatic gear transmission.
Prefabrication of the directional control valve actuators is also simplified due to their assembly-specific design. Thus, it is no longer necessary to encapsulate each directional control valve by itself in a fluid-type manner. The only rubber ring seal needed on the directional control valve itself is a mass produced product.
If, in advantageous development of the assembly-specific directional control valve actuators, their valve bodies are easily exchangeable, the directional control valve drives can also be produced as standard components and be equipped with different valve bodies depending on application.
The valve sealing seats corresponding to the valve bodies of the directional control valve actuators are integrated into the base element and are detached from the prefabricated directional control valve actuators. The valve sealing seats are inserted into pressure feed paths and connected to return valves, which are opened when the magnetic tube of the relevant directional control valve actuator is plugged in or only when the directional control valve actuator has been plugged in and actuated. A longitudinal extension of the valve body, which is parallel to the stroke direction of the valve body, opens the return valves upon valve body insertion or insertion and actuation. The respective pressure connection is blocked, for example during a repair exchange of a directional control valve actuator, directly when it is unplugged from the socket of the base element. At the same time, such a return valve can also advantageously serve as another directional control valve sealing seat for producing a 3/2-way valve as described below.
It is true that a multi-way valve produced in sandwich-style is already known from German Published Unexamined Patent Application No. 3,313,791. In this valve, a single large-area membrane seal is clamped between two housing parts. Both housing parts are provided with integrated fluid and valve paths and, in addition, one housing part also has inserted valve sealing seats which are fluidically arranged between two valve paths. However, in this case certain area selections of the membrane seal are used as valve bodies which can be charged on both sides with fluid pressure and can be moved in the direction of the lower pressure in the case of pressure difference. The area sections can rest on the valve sealing seats and thus block the fluid passage into the valve unit concerned. Apart from the fact that the known arrangement is functionally a single multi-way valve, the individual valve elements can only be switched by fluid pressure differences and not arbitrarily independently of one another. German Published Unexamined Patent Application No. 3,313,791, therefore, does not reveal any indication of the construction of an electromagnetic directional control valve assembly in sandwich-style according to the present invention.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.